Siebe Thissen is historian and philosopher and is associated with the Centre Of The Arts in Rotterdam. In his 1990 history masterthesis he unravelled the battle between Catholic priest Ludo Gompertz and Jewish capitalist entrepreneur Lodewijk Pincoffs at Feijenoord, Rotterdam. His PhD research The Spinozists (2000) mapped the influence of religious and anti-religious freethinkers in the Netherlands.